|
(11) | EP 0 692 610 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||
| (54) | Downhole sleeve valve and stimulation tool |
| (57) A sleeve valve assembly for a downhole tool has a cylindrical housing (101) within
which a sleeve valve member (114) is axially slidable within a radially expanded section
(109) of the housing. The radially expanded section (109) of the housing presents
an inwardly extending stop shoulder (110) at one point along its length and an annular
expansion notch (112b) at another point. The sleeve valve member (114) includes a
radially projecting chamfered boss (119) about its circumference. A portion of the
sleeve valve is longitudinally slotted (117) so as to form collets (118). An outwardly
biased C-ring (122) is disposed about the sleeve valve member (114) within the radially
expanded section (109). The C-ring (122) is initially disposed to be free to travel
axially along the radially expanded section between the boss (119) and the stop shoulder
(110). As the sleeve valve is moved toward an open position, the boss (119), C-ring
(122) and stop shoulder (110) engage each other such that the sleeve valve is releasably
snagged against further axial movement toward the open position. A significant axial
force upon the sleeve valve is required to effect unsnagging. Upon application of
increased axial force, the collets (118) of the sliding sleeve member (114) are forced
radially inward to permit the boss (119) to slip past the C-ring (122). A stimulation
tool incorporating such a sleeve valve assembly is described which permits acid to
be selectively communicated into the surrounding formation. A stimulation tool constructed
in accordance with the present invention is particularly useful for acid stimulation
applications in horizontal well conduits as the snagging feature of the sleeve valve
assembly provides a positive indication that lateral acid flow ports within the shifter
tool have been placed adjacent complementary flow ports in the surrounding housing. |